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CM850 Electronic Control System – Engine Fan Does Not Operate or Operates Erratically

Symptom Tree  t046

This is symptom tree t046
Cause Correction

Programmable parameters or selected features are not correct

Check the programmable parameters and the selected features with an electronic service tool. Set the parameters and features again if necessary. Refer to Procedure 019-078.

 

Manual fan ON/OFF switch and circuit is malfunctioning

Check the manual fan ON/OFF switch and circuit. Refer to Manual Fan ON/OFF Switch, Resistance Check, and Short Circuit to Ground Check in Procedure 019-045.
 

Air conditioner sensor or circuit is malfunctioning

Check the air conditioner sensor and circuit. Refer to Air Conditioner Pressure Switch, Resistance Check, and Short Circuit to Ground Check in Procedure 019-262.

 

Fan clutch actuator or circuit is malfunctioning

Check the fan clutch actuator circuit. Refer to Procedure 019-045.
 

Engine electrical ground is malfunctioning

Check engine ground to chassis and chassis ground to battery negative (-) post. Refer to the OEM service manual and Procedure 013-009 in the Troubleshooting and Repair Manual, ISC, QSC8.3, ISL and QSL9 Engines, Bulletin 4021418..
 
Last Modified:  19-Dec-2003
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